Subcritical crack growth in the cement paste-steel transition zone

Acceleration of percolation for cementitious sensors using conductive paint filler

“…The author compared these effects to that of silica fume and noticed that samples containing carbon black proved to be less resistent to crack propagation and had higher values of strain at maximum compressive stress. The study also showed that cement paste with carbon black contained more voids than a comparable percentage of silica fume and the same water to cement ratio [1] The authors claimed that this agglomeration of CB helped form conductive chains of CB at much lower percolation thresholds, and reported a 40% drop in the percolation threshold on addition of 5% of SBS to a PP/PS polymer.…”

“…Resistive strain gauge working principle Its resistance, according to Ohm's law can be defined as where is the resistivity of the material.Let the element be subjected to a small axial strain d σ. Taking the logarithm of the equation and assuming small changes in length, the derivative of this equation with respect to axial stress σ becomes This can be re-written as(1) and the term can be replaced as as the longitudinal strainThe axial stress also causes a change in cross section area, A. Taking the derivative of log of = 2…”

Contribuição ao estudo dos concretos de elevado desempenho: propriedades mecânicas, durabilidade e microestrutura.

“…cit. ), e na zona de transição pasta de cimento/aço em estudos de R. J. Detwiler(DETWILER, 1990).Por outro lado, existem muitos estudos do efeito da redução da velocidade de hidratação em pastas com sílica ativa, então chamado de "redução de sete dias". Esse efeito influi na melhoria do desempenho das propriedades dos materiais, desempenho esse que é atribuído à demora da reação pozolânica entre a portlandita (Ca(OH)z) e a sílica ativa, coforme relatos de R. J. Detwiler & P. K.Mehta (op.…”